1
|
Niitani K, Nishida R, Futami Y, Nishitani N, Deyama S, Kaneda K. Activation of ventral pallidum-projecting neurons in the nucleus accumbens via 5-HT 2C receptor stimulation regulates motivation for wheel running in male mice. Neuropharmacology 2024; 261:110181. [PMID: 39393590 DOI: 10.1016/j.neuropharm.2024.110181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 10/07/2024] [Accepted: 10/08/2024] [Indexed: 10/13/2024]
Abstract
Rodents have a strong motivation for wheel running; however, the neural mechanisms that regulate their motivation remain unknown. We investigated the possible involvement of serotonin (5-HT) systems in regulating motivation for wheel running in male mice. Systemic administration of a 5-HT1A receptor antagonist (WAY100635) increased the number of wheel rotations, whereas administration of a 5-HT2A or 5-HT2C receptor antagonist (volinanserin or SB242084, respectively) decreased it. In the open field test, neither WAY100635 nor volinanserin affected locomotor activity, whereas SB242084 increased locomotor activity. To identify the brain regions on which these antagonists act, we locally injected these into the motivational circuitry, including the nucleus accumbens (NAc), dorsomedial striatum (DM-Str), and medial prefrontal cortex (mPFC). Injection of SB242084 into the NAc, but not the DM-Str or mPFC, reduced the number of wheel rotations without altering locomotor activity. The local administration of WAY100635 or volinanserin to these brain regions did not affect the number of wheel rotations. Immunohistochemical analyses revealed that wheel running increased the number of c-Fos-positive cells in the NAc medial shell (NAc-MS), which was reduced by systemic SB242084 administration. In vitro slice whole-cell recordings showed that bath application of the 5-HT2C receptor agonist lorcaserin increased the frequency of spontaneous excitatory and inhibitory postsynaptic currents in the ventral tegmental area (VTA)-projecting neurons, whereas it only increased the frequency of spontaneous excitatory postsynaptic currents in ventral pallidum (VP)-projecting neurons in the NAc-MS. These findings suggest that the activation of VP-projecting NAc-MS neurons via 5-HT2C receptor stimulation regulates motivation for wheel running.
Collapse
|
2
|
Deyama S, Aoki S, Sugie R, Kaneda K. Neohesperidin exerts antidepressant-like effect via the mechanistic target of rapamycin complex 1 in the medial prefrontal cortex in male mice. J Pharmacol Sci 2024; 156:82-85. [PMID: 39179338 DOI: 10.1016/j.jphs.2024.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 07/29/2024] [Accepted: 07/30/2024] [Indexed: 08/26/2024] Open
Abstract
Neohesperidin, a citrus flavonoid, shows potential for activating the mechanistic target of rapamycin complex 1 (mTORC1). Here, the antidepressant-like effect of neohesperidin was examined in male ICR mice (naïve mice and mice treated repeatedly with prednisolone, a synthetic glucocorticoid, which induces depression-like behavior). Oral neohesperidin administration exerted an antidepressant-like effect in the forced swim test 1 h post-treatment, in naïve mice; this effect was no longer observed at 24 h. Neohesperidin also reversed prednisolone-induced depression-like behavior. This effect was blocked by infusing rapamycin, an mTORC1 inhibitor, into the medial prefrontal cortex. Neohesperidin may rapidly produce an antidepressant-like effect.
Collapse
|
3
|
Esaki H, Izumi S, Nishikawa K, Nagayasu K, Kaneko S, Nishitani N, Deyama S, Kaneda K. Role of medial prefrontal cortex voltage-dependent potassium 4.3 channels in nicotine-induced enhancement of object recognition memory in male mice. Eur J Pharmacol 2024; 978:176790. [PMID: 38942263 DOI: 10.1016/j.ejphar.2024.176790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 06/26/2024] [Indexed: 06/30/2024]
Abstract
Nicotine has been shown to enhance object recognition memory in the novel object recognition (NOR) test by activating excitatory neurons in the medial prefrontal cortex (mPFC). However, the exact neuronal mechanisms underlying the nicotine-induced activation of mPFC neurons and the resultant memory enhancement remain poorly understood. To address this issue, we performed brain-slice electrophysiology and the NOR test in male C57BL/6J mice. Whole-cell patch-clamp recordings from layer V pyramidal neurons in the mPFC revealed that nicotine augments the summation of evoked excitatory postsynaptic potentials (eEPSPs) and that this effect was suppressed by N-[3,5-Bis(trifluoromethyl)phenyl]-N'-[2,4-dibromo-6-(2H-tetrazol-5-yl)phenyl]urea (NS5806), a voltage-dependent potassium (Kv) 4.3 channel activator. In line with these findings, intra-mPFC infusion of NS5806 suppressed systemically administered nicotine-induced memory enhancement in the NOR test. Additionally, miRNA-mediated knockdown of Kv4.3 channels in mPFC pyramidal neurons enhanced object recognition memory. Furthermore, inhibition of A-type Kv channels by intra-mPFC infusion of 4-aminopyridine was found to enhance object recognition memory, while this effect was abrogated by prior intra-mPFC NS5806 infusion. These results suggest that nicotine augments the summation of eEPSPs via the inhibition of Kv4.3 channels in mPFC layer V pyramidal neurons, resulting in the enhancement of object recognition memory.
Collapse
|
4
|
Deyama S, Sugie R, Tabata M, Kaneda K. Antidepressant-like effects of tomatidine and tomatine, steroidal alkaloids from unripe tomatoes, via activation of mTORC1 in the medial prefrontal cortex in lipopolysaccharide-induced depression model mice. Nutr Neurosci 2024; 27:795-808. [PMID: 37704369 DOI: 10.1080/1028415x.2023.2254542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
ABSTRACTKetamine, an N-methyl-D-aspartate receptor antagonist, produces rapid antidepressant effects in patients with treatment-resistant depression. However, owing to the undesirable adverse effects of ketamine, there is an urgent need for developing safer and more effective prophylactic and therapeutic interventions for depression. Preclinical studies have demonstrated that activation of the mechanistic target of rapamycin complex 1 (mTORC1) in the medial prefrontal cortex (mPFC) mediates the rapid antidepressant effects of ketamine. The steroidal alkaloid tomatidine and its glycoside α-tomatine (tomatine) can activate mTORC1 signaling in peripheral tissues/cells. We examined whether tomatidine and tomatine exerted prophylactic and therapeutic antidepressant-like actions via mPFC mTORC1 activation using a mouse model of lipopolysaccharide (LPS)-induced depression. Male mice were intraperitoneally (i.p.) administered tomatidine/tomatine before and after the LPS challenge to test their prophylactic and therapeutic effects, respectively. LPS-induced depression-like behaviors in the tail suspension test (TST) and forced swim test (FST) were significantly reversed by prophylactic and therapeutic tomatidine/tomatine administration. LPS-induced anhedonia in the female urine sniffing test was reversed by prophylactic, but not therapeutic, injection of tomatidine, and by prophylactic and therapeutic administration of tomatine. Intra-mPFC infusion of rapamycin, an mTORC1 inhibitor, blocked the prophylactic and therapeutic antidepressant-like effects of tomatidine/tomatine in TST and FST. Moreover, both tomatidine and tomatine produced antidepressant-like effects in ovariectomized female mice, a model of menopause-associated depression. These results indicate that tomatidine and tomatine exert prophylactic and therapeutic antidepressant-like effects via mTORC1 activation in the mPFC and suggest these compounds as promising candidates for novel prophylactic and therapeutic agents for depression.
Collapse
|
5
|
Deyama S, Li X, Duman RS. Neuron-specific deletion of VEGF or its receptor Flk-1 occludes the antidepressant-like effects of desipramine and fluoxetine in mice. Neuropsychopharmacol Rep 2024; 44:246-249. [PMID: 37960997 PMCID: PMC10932798 DOI: 10.1002/npr2.12393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 10/10/2023] [Accepted: 10/18/2023] [Indexed: 11/15/2023] Open
Abstract
Vascular endothelial growth factor (VEGF) signaling is known to be involved in the antidepressant-like effects of conventional antidepressants, such as desipramine (DMI), a tricyclic antidepressant, and fluoxetine (FLX), a selective serotonin reuptake inhibitor; however, the precise role of neuronal VEGF signaling in mediating these effects remains unclear. Using mice with excitatory neuron-specific deletion of VEGF and its receptor, fetal liver kinase 1 (Flk-1) in the forebrain, we examined the effects of forebrain excitatory neuron-specific deletion of VEGF or Flk-1 on the antidepressant-like effects of repeated DMI and chronic FLX administration in the forced swim test (FST). Repeated intraperitoneal (i.p.) injections of DMI (10, 10, and 20 mg/kg at 24, 4, and 1 h before the FST, respectively) significantly decreased immobility in control mice; however, this effect was completely blocked in mice with neuron-specific VEGF or Flk-1 deletion. Although chronic treatment with FLX (18 mg/kg/day, i.p.) did not impact immobility in control mice 1 day after the 22nd injection, immobility was significantly reduced 1 day after the preswim and the 23rd FLX injection. However, in mice with neuron-specific Flk-1 deletion, chronic FLX treatment significantly increased immobility in the preswim and failed to produce antidepressant-like effects. Collectively, these findings indicate that neuronal VEGF-Flk-1 signaling contributes to the antidepressant-like actions of conventional antidepressants.
Collapse
|
6
|
Saito A, Murata H, Niitani K, Nagasaki J, Otoda A, Chujo Y, Yanagida J, Nishitani N, Deyama S, Kaneda K. Social defeat stress enhances the rewarding effects of cocaine through α 1A adrenoceptors in the medial prefrontal cortex of mice. Neuropharmacology 2024; 242:109757. [PMID: 37839511 DOI: 10.1016/j.neuropharm.2023.109757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/07/2023] [Accepted: 10/07/2023] [Indexed: 10/17/2023]
Abstract
Various stressors potentiate the rewarding effects of cocaine and contribute to cocaine cravings. However, it remains unclear whether psychosocial stress enhances the rewarding effects of cocaine. Accordingly, this study employed a cocaine-conditioned place preference (CPP) paradigm combined with social defeat (SD) exposure to investigate the effects of acute SD stress on cocaine reward in male mice. We found that SD stress immediately before the posttest significantly increased cocaine CPP, and systemic blockade of α1 adrenoceptors, but not β adrenoceptors, suppressed this increase. Fiber photometry recordings with GRABNE1m sensors revealed increased noradrenaline (NA) levels in the medial prefrontal cortex (mPFC) in test mice in response to attacks by aggressor mice during SD. Moreover, the SD stress-induced enhancement of CPP was effectively suppressed by intra-mPFC infusion of an α1 adrenoceptor antagonist. In vitro whole-cell recordings demonstrated that silodosin, an α1A, but not α1B or α1D, adrenoceptor antagonist, inhibited NA-induced depolarizing currents and facilitation of excitatory synaptic transmissions. Consistently, intra-mPFC silodosin infusion significantly suppressed the SD stress-induced CPP enhancement. Conversely, intra-mPFC infusion of α1A adrenoceptor agonist augmented cocaine CPP in the absence of stress exposure. Additionally, intranasal silodosin administration attenuated the SD stress-induced enhancement of CPP, and chemogenetic inhibition of mPFC excitatory neurons also suppressed the SD stress-induced CPP enhancement. Together, these findings suggest that NA stimulation of α1A adrenoceptors and the subsequent activation of mPFC pyramidal cells may contribute to SD stress-induced amplification of the rewarding effects of cocaine, and intranasal silodosin administration may hold therapeutic potential for mitigating stress-associated cocaine craving.
Collapse
|
7
|
Deyama S, Minami M, Kaneda K. [Resolvin E1 as a potential lead for the treatment of depression]. Nihon Yakurigaku Zasshi 2024; 159:210-213. [PMID: 38945902 DOI: 10.1254/fpj.23008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Typical monoamine-based antidepressants have significant limitations, including a time lag for therapeutic response and low efficacy (more than one-third of depressed patients fail to respond to multiple antidepressant medications and are considered treatment-resistant). Conversely, ketamine, an N-methyl-D-aspartate receptor antagonist, exhibits rapid and sustained antidepressant actions in patients with treatment-resistant depression. However, clinical use of ketamine is limited due to its serious side effects. Thus, there is a significant need to develop novel ketamine-like antidepressants with fewer side effects. We previously demonstrated that intracerebroventricular infusion of resolvins (RvD1, RvD2, RvE1, RvE2, and RvE3), specialized pro-resolving lipid mediators derived from docosahexaenoic and eicosapentaenoic acids, produce antidepressant-like effects in mouse models of depression. Among resolvins, RvE1 produces the most potent antidepressant-like effects likely via ChemR23 in several mouse models of depression. Local infusion of RvE1 into the medial prefrontal cortex (mPFC) or dorsal hippocampal dentate gyrus (DG) also produces antidepressant-like effects, suggesting that these brain regions are sites of action of RvE1. Additionally, intranasal (i.n.) administration of RvE1 produces antidepressant-like effects through mechanisms similar to ketamine: activity-dependent release of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), and subsequent mechanistic target of rapamycin complex 1 (mTORC1) activation in the mPFC play a crucial role in the rapid and sustained antidepressant-like actions of i.n. RvE1. Moreover, the antidepressant-like effects of i.n. RvE1 require BDNF and VEGF release, but not mTORC1 activation, in the dorsal DG. These findings suggest that RvE1 can be a promising lead for a novel rapid-acting antidepressant.
Collapse
|
8
|
Esaki H, Deyama S, Izumi S, Katsura A, Nishikawa K, Nishitani N, Kaneda K. Varenicline enhances recognition memory via α7 nicotinic acetylcholine receptors in the medial prefrontal cortex in male mice. Neuropharmacology 2023; 239:109672. [PMID: 37506875 DOI: 10.1016/j.neuropharm.2023.109672] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
Previous studies postulated that chronic administration of varenicline, a partial and full agonist at α4β2 and α7 nicotinic acetylcholine receptors (nAChRs), respectively, enhances recognition memory. However, whether its acute administration is effective, on which brain region(s) it acts, and in what signaling it is involved, remain unknown. To address these issues, we conducted a novel object recognition test using male C57BL/6J mice, focusing on the medial prefrontal cortex (mPFC), a brain region associated with nicotine-induced enhancement of recognition memory. Systemic administration of varenicline before the training dose-dependently enhanced recognition memory. Intra-mPFC varenicline infusion also enhanced recognition memory, and this enhancement was blocked by intra-mPFC co-infusion of a selective α7, but not α4β2, nAChR antagonist. Consistent with this, intra-mPFC infusion of a selective α7 nAChR agonist augmented object recognition memory. Furthermore, intra-mPFC co-infusion of U-73122, a phospholipase C (PLC) inhibitor, or 2-aminoethoxydiphenylborane (2-APB), an inositol trisphosphate (IP3) receptor inhibitor, suppressed the varenicline-induced memory enhancement, suggesting that α7 nAChRs may also act as Gq-coupled metabotropic receptors. Additionally, whole-cell recordings from mPFC layer V pyramidal neurons in vitro revealed that varenicline significantly increased the summation of evoked excitatory postsynaptic potentials, and this effect was suppressed by U-73122 or 2-APB. These findings suggest that varenicline might acutely enhance recognition memory via mPFC α7 nAChR stimulation, followed by mPFC neuronal excitation, which is mediated by the activation of PLC and IP3 receptor signaling. Our study provides evidence supporting the potential repositioning of varenicline as a treatment for cognitive impairment.
Collapse
|
9
|
Niitani K, Ito S, Wada S, Izumi S, Nishitani N, Deyama S, Kaneda K. Noradrenergic stimulation of α 1 adrenoceptors in the medial prefrontal cortex mediates acute stress-induced facilitation of seizures in mice. Sci Rep 2023; 13:8089. [PMID: 37208473 DOI: 10.1038/s41598-023-35242-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/15/2023] [Indexed: 05/21/2023] Open
Abstract
Stress is one of the critical facilitators for seizure induction in patients with epilepsy. However, the neural mechanisms underlying this facilitation remain poorly understood. Here, we investigated whether noradrenaline (NA) transmission enhanced by stress exposure facilitates the induction of medial prefrontal cortex (mPFC)-originated seizures. In mPFC slices, whole-cell current-clamp recordings revealed that bath application of picrotoxin induced sporadic epileptiform activities (EAs), which consisted of depolarization with bursts of action potentials in layer 5 pyramidal cells. Addition of NA dramatically shortened the latency and increased the number of EAs. Simultaneous whole-cell and field potential recordings revealed that the EAs are synchronous in the mPFC local circuit. Terazosin, but not atipamezole or timolol, inhibited EA facilitation, indicating the involvement of α1 adrenoceptors. Intra-mPFC picrotoxin infusion induced seizures in mice in vivo. Addition of NA substantially shortened the seizure latency, while co-infusion of terazosin into the mPFC inhibited the effect of NA. Finally, acute restraint stress shortened the latency of intra-mPFC picrotoxin infusion-induced seizures, whereas prior infusion of terazosin reversed this stress-induced shortening of seizure latency. Our findings suggest that stress facilitates the induction of mPFC-originated seizures via NA stimulation of α1 adrenoceptors.
Collapse
|
10
|
Esaki H, Sasaki Y, Nishitani N, Kamada H, Mukai S, Ohshima Y, Nakada S, Ni X, Deyama S, Kaneda K. Role of 5-HT 1A receptors in the basolateral amygdala on 3,4-methylenedioxymethamphetamine-induced prosocial effects in mice. Eur J Pharmacol 2023; 946:175653. [PMID: 36907260 DOI: 10.1016/j.ejphar.2023.175653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/14/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023]
Abstract
3,4-methylenedioxymethamphetamine (MDMA), a recreational drug, induces euphoric sensations and psychosocial effects, such as increased sociability and empathy. Serotonin, also called 5-hydroxytryptamine (5-HT), is a neurotransmitter that has been associated with MDMA-induced prosocial effects. However, the detailed neural mechanisms remain elusive. In the present study, we investigated whether 5-HT neurotransmission in the medial prefrontal cortex (mPFC) and the basolateral nucleus of amygdala (BLA) is involved in MDMA-induced prosocial effects using the social approach test in male ICR mice. Systemic administration of (S)-citalopram, a selective 5-HT transporter inhibitor, before administration of MDMA failed to suppress MDMA-induced prosocial effects. On the other hand, systemic administration of the 5-HT1A receptor antagonist WAY100635, but not 5-HT1B, 5-HT2A, 5-HT2C, or 5-HT4 receptor antagonist, significantly suppressed MDMA-induced prosocial effects. Furthermore, local administration of WAY100635 into the BLA but not into the mPFC suppressed MDMA-induced prosocial effects. Consistent with this finding, intra-BLA MDMA administration significantly increased sociability. Together, these results suggest that MDMA induces prosocial effects through the stimulation of 5-HT1A receptors in the BLA.
Collapse
|
11
|
Deyama S, Aoki S, Sugie R, Fukuda H, Shuto S, Minami M, Kaneda K. Intranasal Administration of Resolvin E1 Produces Antidepressant-Like Effects via BDNF/VEGF-mTORC1 Signaling in the Medial Prefrontal Cortex. Neurotherapeutics 2023; 20:484-501. [PMID: 36622634 PMCID: PMC10121976 DOI: 10.1007/s13311-022-01337-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2022] [Indexed: 01/10/2023] Open
Abstract
Intracerebroventricular infusion of resolvin E1 (RvE1), a bioactive metabolite derived from eicosapentaenoic acid, exerts antidepressant-like effects in a mouse model of lipopolysaccharide (LPS)-induced depression; these effects are blocked by systemic injection of rapamycin, a mechanistic target of rapamycin complex 1 (mTORC1) inhibitor. Additionally, local infusion of RvE1 into the medial prefrontal cortex (mPFC) or dorsal hippocampal dentate gyrus (DG) produces antidepressant-like effects. To evaluate the potential of RvE1 for clinical use, the present study examined whether treatment with RvE1 via intranasal (i.n.) route, a non-invasive route for effective drug delivery to the brain, produces antidepressant-like effects in LPS-challenged mice using tail suspension and forced swim tests. Intranasal administration of RvE1 significantly attenuated LPS-induced immobility, and these antidepressant-like effects were completely blocked by an AMPA receptor antagonist or L-type voltage-dependent Ca2+ channel blocker. The antidepressant-like effects of both i.n. and intra-mPFC administrations of RvE1 were blocked by intra-mPFC infusion of a neutralizing antibody (nAb) for brain-derived neurotrophic factor (BDNF) or vascular endothelial growth factor (VEGF). Intra-mPFC infusion of rapamycin completely blocked the antidepressant-like effects of both i.n. and intra-mPFC administrations of RvE1 as well as those of intra-mPFC infusion of BDNF and VEGF. Moreover, i.n. RvE1 produced antidepressant-like effects via mTORC1 activation in the mPFC of a mouse model of repeated prednisolone-induced depression. Intra-dorsal DG infusion of BDNF and VEGF nAbs, but not rapamycin, blocked the antidepressant-like effects of i.n. RvE1. These findings suggest that i.n. administration of RvE1 produces antidepressant-like effects through activity-dependent BDNF/VEGF release in the mPFC and dorsal DG, and mTORC1 activation in the mPFC, but not in the dorsal DG. Thus, RvE1 can be a promising candidate for a novel rapid-acting antidepressant.
Collapse
|
12
|
Deyama S, Kaneda K. Role of neurotrophic and growth factors in the rapid and sustained antidepressant actions of ketamine. Neuropharmacology 2023; 224:109335. [PMID: 36403852 DOI: 10.1016/j.neuropharm.2022.109335] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/10/2022] [Accepted: 11/12/2022] [Indexed: 11/18/2022]
Abstract
The neurotrophic hypothesis of depression proposes that reduced levels of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) contribute to neuronal atrophy or loss in the prefrontal cortex (PFC) and hippocampus and impaired hippocampal adult neurogenesis, which are associated with depressive symptoms. Chronic, but acute, treatment with typical monoaminergic antidepressants can at least partially reverse these deficits, in part via induction of BDNF and/or VEGF expression, consistent with their delayed onset of action. Ketamine, an N-methyl-d-aspartate receptor antagonist, exerts rapid and sustained antidepressant effects. Rodent studies have revealed that ketamine rapidly increases BDNF and VEGF release and/or expression in the PFC and hippocampus, which in turn increases the number and function of spine synapses in the PFC and hippocampal neurogenesis. Ketamine also induces the persistent release of insulin-like growth factor 1 (IGF-1) in the PFC of male mice. These neurotrophic effects of ketamine are associated with its rapid and sustained antidepressant effects. In this review, we first provide an overview of the neurotrophic hypothesis of depression and then discuss the role of BDNF, VEGF, IGF-1, and other growth factors (IGF-2 and transforming growth factor-β1) in the antidepressant effects of ketamine and its enantiomers. This article is part of the Special Issue on 'Ketamine and its Metabolites'.
Collapse
|
13
|
Deyama S. [Elucidation of the Mechanisms Underlying the Rapid Antidepressant Actions of Ketamine and Search for Possible Candidates for Novel Rapid-acting Antidepressants]. YAKUGAKU ZASSHI 2023; 143:713-720. [PMID: 37661437 DOI: 10.1248/yakushi.23-00111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Ketamine, an N-methyl-D-aspartate receptor antagonist, elicits swift antidepressant effects even in subjects with treatment-resistant depression. Nonetheless, owing to the serious adverse effects associated with ketamine, including psychotomimetic effects, the development of safer rapid-acting antidepressants is imperative. The elucidation of the mechanisms underlying the antidepressant effects of ketamine will facilitate the advancement of these alternative treatments. Previous preclinical studies have indicated that the antidepressant properties of ketamine are mediated by the activity-dependent release of brain-derived neurotrophic factor (BDNF) and the subsequent activation of mechanistic target of rapamycin complex 1 (mTORC1) in the medial prefrontal cortex (mPFC). Our research has demonstrated that ketamine exerts antidepressant-like effects by inducing the release of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF-1) in the mPFC. Furthermore, our recent findings have revealed that resolvins (RvD1, RvD2, RvE1, RvE2, and RvE3), which are bioactive lipid mediators derived from docosahexaenoic and eicosapentaenoic acids, exhibit antidepressant-like effects in rodent models. Notably, the antidepressant-like effects of RvD1, RvD2, and RvE1 require mTORC1 activation. Moreover, the intranasal administration of RvE1 elicits rapid antidepressant-like effects through the release of BDNF and VEGF in the mPFC and hippocampal dentate gyrus (DG), as well as mTORC1 activation in the mPFC, albeit not in the DG. These findings strongly suggest that resolvins, particularly RvD1, RvD2, and RvE1, hold promise as prospective candidates for novel, safer, and rapid-acting antidepressants.
Collapse
|
14
|
Deyama S, Kaneda K, Minami M. Resolution of depression: antidepressant actions of resolvins. Neurosci Res 2022:S0168-0102(22)00266-8. [PMID: 36272561 DOI: 10.1016/j.neures.2022.10.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022]
Abstract
Major depressive disorder, one of the most widespread mental illnesses, brings about enormous individual and socioeconomic consequences. Conventional monoaminergic antidepressants require weeks to months to produce a therapeutic response, and approximately one-third of the patients fail to respond to these drugs and are considered treatment-resistant. Although recent studies have demonstrated that ketamine, an N-methyl-D-aspartate receptor antagonist, produces rapid antidepressant effects in treatment-resistant patients, it also has undesirable side effects. Hence, rapid-acting antidepressants that have fewer adverse effects than ketamine are urgently required. D-series (RvD1-RvD6) and E-series (RvE1-RvE4) resolvins are endogenous lipid mediators derived from docosahexaenoic and eicosapentaenoic acids, respectively. These mediators reportedly play a pivotal role in the resolution of acute inflammation. In this review, we reveal that intracranial infusions of RvD1, RvD2, RvE1, RvE2, and RvE3 produce antidepressant-like effects in various rodent models of depression. Moreover, the behavioral effects of RvD1, RvD2, and RvE1 are mediated by the activation of the mechanistic target of rapamycin complex 1, which is essential for the antidepressant-like actions of ketamine. Finally, we briefly provide our perspective on the possible role of endogenous resolvins in stress resilience.
Collapse
|
15
|
Zhang T, Nishitani N, Niitani K, Nishida R, Futami Y, Deyama S, Kaneda K. A spatiotemporal increase of neuronal activity accompanies the motivational effect of wheel running in mice. Behav Brain Res 2022; 432:113981. [PMID: 35777550 DOI: 10.1016/j.bbr.2022.113981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 06/24/2022] [Accepted: 06/26/2022] [Indexed: 11/19/2022]
Abstract
Spatiotemporal patterns of neuronal activity underlying the motivational effect of rotating running wheels (RWs) in rodents remain largely undetermined. Here, we investigated changes of neuronal activity among brain regions associated with motivation across different intensities of motivation for RWs in mice. Daily exposure to RWs gradually increased rotation number, then became stable after approximately 3 weeks. Immunohistochemical analyses revealed that the number of c-Fos (a neuronal activity marker)-positive cells increased in the medial prefrontal cortex (mPFC), core and shell of the nucleus accumbens (NAc), dorsal striatum (Str), and lateral septum (LS) at day 1, day 9, and days 20-24, in a time-dependent manner. Additionally, despite exposure to locked RWs for over 7 days after establishing stable rotation with 3-week RW access, increased c-Fos expression was still observed in most of these brain areas. Furthermore, daily overnight RW access developed stable rotation by day 6, with high and low rotation numbers at the start and end of the overnight session, respectively. The number of c-Fos-positive cells at the start of RW rotation was significantly higher than at the end of RW rotation in most brain regions. Furthermore, after establishing stable rotation, the number of c-Fos-positive cells increased in the mPFC and shell of the NAc of mice that only observed RWs. These findings suggest that the subareas of the mPFC and NAc may be critically involved in the motivational effects of RW rotations.
Collapse
|
16
|
Aoki S, Deyama S, Sugie R, Ishimura K, Fukuda H, Shuto S, Minami M, Kaneda K. The antidepressant-like effect of resolvin E1 in repeated prednisolone-induced depression model mice. Behav Brain Res 2022; 418:113676. [PMID: 34801580 DOI: 10.1016/j.bbr.2021.113676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/30/2021] [Accepted: 11/15/2021] [Indexed: 12/30/2022]
Abstract
Resolvin E1 (RvE1) is an anti-inflammatory lipid mediator derived from eicosapentaenoic acid. We previously demonstrated that intracerebroventricular (i.c.v.) and intra-medial prefrontal cortex (mPFC) infusions of RvE1 produce antidepressant-like effects in a lipopolysaccharide-induced depression mouse model. To further confirm the antidepressant-like effect of RvE1, the present study examined whether RvE1 ameliorated depression-like behavior induced by repeated injections of prednisolone (PSL), a synthetic glucocorticoid, in male ICR mice. We first ascertained whether repeated subcutaneous treatment with PSL (50 mg/kg, once a day) affected locomotor activity and anxiety-like behavior in the open field test (OFT; after a 5-day PSL treatment) and induced depression-like behavior in the tail suspension test (TST; after a 6-day PSL treatment) and forced swim test (FST; after a 7-day PSL treatment). Repeated PSL injections significantly increased immobility in the FST, which was not ameliorated by acute desipramine treatment (30 mg/kg, i.p.), but not in the TST, without affecting locomotor activity and anxiety-like behavior in the OFT. Subsequently, we investigated the therapeutic effects of i.c.v. (1 ng) and intra-mPFC (50 pg/side) infusions of RvE1 in the repeated PSL-induced depression mouse model using the OFT and FST after 5- and 6-day PSL treatments, respectively. The repeated PSL-induced increase in immobility in the FST was significantly attenuated by both i.c.v. and intra-mPFC infusions of RvE1 without affecting the locomotor activity and anxiety-like behavior. In addition, a single i.c.v. infusion of RvE1 immediately before the first or fourth injection of PSL also attenuated PSL-induced depression-like behavior in the FST, suggesting the preventive effect of RvE1. These results indicate that RvE1 produces antidepressant-like effects in a mouse model of repeated PSL-induced depression.
Collapse
|
17
|
Suzuki H, Otsuka T, Hitora-Imamura N, Ishimura K, Fukuda H, Fujiwara K, Shuto S, Deyama S, Minami M. Resolvin E1 Attenuates Chronic Pain-Induced Depression-Like Behavior in Mice: Possible Involvement of Chemerin Receptor ChemR23. Biol Pharm Bull 2021; 44:1548-1550. [PMID: 34602564 DOI: 10.1248/bpb.b21-00461] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antidepressant effect of eicosapentaenoic acid-derived bioactive lipid, resolvin E1 (RvE1), was examined in a murine model of chronic pain-induced depression using a tail suspension test. Because RvE1 reportedly possesses agonistic activity on a chemerin receptor ChemR23, we also examined the antidepressant effect of chemerin. Two weeks after surgery for unilateral spared nerve injury to prepare neuropathic pain model mice, immobility time was measured in a tail suspension test. Chronic pain significantly increased immobility time, and this depression-like behavior was attenuated by intracerebroventricular injection of RvE1 (1 ng) or chemerin (500 ng). These results demonstrate that RvE1 exerts an antidepressant effect in a murine model of chronic pain-induced depression, which is likely to be via ChemR23. RvE1 and its receptor may be promising targets to develop novel antidepressants.
Collapse
|
18
|
Esaki H, Izumi S, Fukao A, Nishitani N, Deyama S, Kaneda K. Nicotine enhances object recognition memory through inhibition of voltage-dependent potassium 7 channels in the medial prefrontal cortex of mice. J Pharmacol Sci 2021; 147:58-61. [PMID: 34294373 DOI: 10.1016/j.jphs.2021.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 04/23/2021] [Accepted: 05/06/2021] [Indexed: 11/19/2022] Open
Abstract
Nicotine administration enhances object recognition memory. However, target brain regions and cellular mechanisms underlying the nicotine effects remain unclear. In mice, the novel object recognition test revealed that systemic nicotine administration before training enhanced object recognition memory. Moreover, this effect was inhibited by infusion of retigabine, a selective voltage-dependent potassium 7 (Kv7) channel opener, into the medial prefrontal cortex (mPFC) before nicotine administration. Additionally, infusion of XE-991, a selective Kv7 channel blocker, into the mPFC before training enhanced object recognition memory. Therefore, Kv7 channels in the mPFC may be at least partly involved in nicotine-induced enhancement of object recognition memory.
Collapse
|
19
|
Suzuki H, Hitora-Imamura N, Deyama S, Minami M. Resolvin D2 attenuates chronic pain-induced depression-like behavior in mice. Neuropsychopharmacol Rep 2021; 41:426-429. [PMID: 34291613 PMCID: PMC8411310 DOI: 10.1002/npr2.12198] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/06/2021] [Accepted: 07/09/2021] [Indexed: 12/28/2022] Open
Abstract
AIM We previously demonstrated that intracerebroventricular injection of resolvin D2 (RvD2), a bioactive lipid mediator derived from docosahexaenoic acid, ameliorated depression-like behavior in lipopolysaccharide-induced and chronic mild stress-induced mouse models of depression. In the present study, we examined the antidepressant effect of RvD2 on chronic pain-induced depression-like behavior. METHODS To prepare the neuropathic pain model, mice were subjected to surgery for unilateral spared nerve injury. Two weeks after surgery, the antidepressant effect of RvD2 was examined using the tail suspension test. RESULTS Chronic pain significantly increased immobility time, and this depression-like behavior was attenuated by intracerebroventricular injection of RvD2 (10 ng). No effect of RvD2 on the locomotor activity was observed. CONCLUSION RvD2 produces an antidepressant effect in a murine model of chronic pain-induced depression and may be a promising lead for the development of novel antidepressants.
Collapse
|
20
|
Deyama S, Minami M, Kaneda K. Resolvins as potential candidates for the treatment of major depressive disorder. J Pharmacol Sci 2021; 147:33-39. [PMID: 34294370 DOI: 10.1016/j.jphs.2021.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/06/2021] [Accepted: 05/10/2021] [Indexed: 02/06/2023] Open
Abstract
In contrast with the delayed onset of therapeutic responses and relatively low efficacy of currently available monoamine-based antidepressants, a single subanesthetic dose of ketamine, an N-methyl-D-aspartate receptor antagonist, produces rapid and sustained antidepressant actions even in patients with treatment-resistant depression. However, since the clinical use of ketamine as an antidepressant is limited owing to its adverse effects, such as psychotomimetic/dissociative effects and abuse potential, there is an unmet need for novel rapid-acting antidepressants with fewer side effects. Preclinical studies have revealed that the antidepressant actions of ketamine are mediated via the release of brain-derived neurotrophic factor and vascular endothelial growth factor, with the subsequent activation of mechanistic target of rapamycin complex 1 (mTORC1) in the medial prefrontal cortex. Recently, we demonstrated that resolvins (RvD1, RvD2, RvE1, RvE2 and RvE3), endogenous lipid mediators generated from n-3 polyunsaturated fatty acids (docosahexaenoic and eicosapentaenoic acids), exert antidepressant effects in a rodent model of depression, and that the antidepressant effects of RvD1, RvD2, and RvE1 necessitate mTORC1 activation. In this review, we first provide an overview of the mechanisms underlying the antidepressant effects of ketamine and other rapid-acting agents. We then discuss the possibility of using resolvins as novel therapeutic candidates for depression.
Collapse
|
21
|
Izumi S, Domoto M, Esaki H, Sasase H, Nishitani N, Deyama S, Kaneda K. Nicotine Enhances Firing Activity of Layer 5 Pyramidal Neurons in the Medial Prefrontal Cortex through Inhibition of Kv7 Channels. Biol Pharm Bull 2021; 44:724-731. [PMID: 33952828 DOI: 10.1248/bpb.b21-00137] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nicotine enhances attention, working memory and recognition. One of the brain regions associated with these effects of nicotine is the medial prefrontal cortex (mPFC). However, cellular mechanisms that induce the enhancing effects of nicotine remain unclear. To address this issue, we performed whole-cell patch-clamp recordings from mPFC layer 5 pyramidal neurons in slices of C57BL/6J mice. Shortly (approx. 2 min) after bath application of nicotine, the number of action potentials, which were elicited by depolarizing current injection, was increased, and this increase persisted for over 5 min. The effect of nicotine was blocked by the α4β2 nicotinic acetylcholine receptor (nAChR) antagonist dihydro-β-erythroidine, α7 nAChR antagonist methyllycaconitine, or intracellular perfusion with the Ca2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA). Additionally, the voltage-dependent potassium 7 (Kv7) channel blocker, 10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone dihydrochloride (XE-991), as well as nicotine, shortened the spike threshold latency and increased the spike numbers. By contrast, the Kv7 channel opener, retigabine reduced the number of firings, and the addition of nicotine did not increase the spike numbers. These results indicate that nicotine induces long-lasting enhancement of firing activity in mPFC layer 5 pyramidal neurons, which is mediated by the stimulation of the α4β2 and α7 nAChRs and subsequent increase in intracellular Ca2+ levels followed by the suppression of the Kv7 channels. The novel effect of nicotine might underlie the nicotine-induced enhancement of attention, working memory and recognition.
Collapse
|
22
|
Esaki H, Izumi S, Fukao A, Ito S, Nishitani N, Deyama S, Kaneda K. Nicotine Enhances Object Recognition Memory via Stimulating α4β2 and α7 Nicotinic Acetylcholine Receptors in the Medial Prefrontal Cortex of Mice. Biol Pharm Bull 2021; 44:1007-1013. [PMID: 34193682 DOI: 10.1248/bpb.b21-00314] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nicotine has been known to enhance recognition memory in various species. However, the brain region where nicotine acts and exerts its effect remains unclear. Since the medial prefrontal cortex (mPFC) is associated with memory, we examined the role of the mPFC in nicotine-induced enhancement of recognition memory using the novel object recognition test in male C57BL/6J mice. Systemic nicotine administration 10 min before training session significantly enhanced object recognition memory in test session that was performed 24 h after the training. Intra-mPFC infusion of mecamylamine, a non-selective nicotinic acetylcholine receptor (nAChR) antagonist, 5 min before nicotine administration blocked the effect of nicotine. Additionally, intra-mPFC infusion of dihydro-β-erythroidine, a selective α4β2 nAChR antagonist, or methyllycaconitine, a selective α7 nAChR antagonist, significantly suppressed the nicotine-induced object recognition memory enhancement. Finally, intra-mPFC infusion of nicotine 1 min before the training session augmented object recognition memory in a dose-dependent manner. These findings suggest that mPFC α4β2 and α7 nAChRs mediate the nicotine-induced object recognition memory enhancement.
Collapse
|
23
|
Chu J, Deyama S, Li X, Motono M, Otoda A, Saito A, Esaki H, Nishitani N, Kaneda K. Role of 5-HT 1A receptor-mediated serotonergic transmission in the medial prefrontal cortex in acute restraint stress-induced augmentation of rewarding memory of cocaine in mice. Neurosci Lett 2020; 743:135555. [PMID: 33352288 DOI: 10.1016/j.neulet.2020.135555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/28/2020] [Accepted: 12/02/2020] [Indexed: 11/27/2022]
Abstract
Stress enhances cocaine craving. We recently reported that acute restraint stress increases cocaine conditioned place preference (CPP) in mice; however, the underlying mechanisms remain unclear. This study aimed to examine the role of serotonergic transmission in the medial prefrontal cortex (mPFC) in cocaine CPP enhancement by acute restraint stress, which increases extracellular serotonin (5-HT) levels in the mPFC. Intra-mPFC infusion of the selective serotonin reuptake inhibitor (S)-citalopram prior to the test session significantly increased the cocaine CPP score under non-stressed conditions. This is indicative of the substantial role of increased mPFC 5-HT levels in cocaine CPP enhancement. Moreover, intra-mPFC and systemic administration of the 5-HT1A receptor antagonist WAY100635 immediately before restraint stress exposure significantly attenuated stress-induced cocaine CPP enhancement. Our findings suggest that enhanced serotonergic transmission via 5-HT1A receptors in the mPFC is involved in acute stress-induced augmentation of rewarding memory of cocaine; moreover, the 5-HT1A receptor could be a therapeutic target for stress-induced cocaine craving.
Collapse
|
24
|
Deyama S. [Resolvins as novel targets for rapid-acting antidepressants]. Nihon Yakurigaku Zasshi 2020; 155:381-385. [PMID: 33132254 DOI: 10.1254/fpj.20044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Conventional monoaminergic antidepressants have significant limitations, including delayed onset of therapeutic response and relatively low efficacy. Recent studies reveal that the NMDA receptor antagonist ketamine produces rapid and sustained antidepressant effects in treatment-resistant depressed patients. Despite the unique antidepressant efficacy, clinical use of ketamine as an antidepressant is limited due to its serious drawbacks, such as abuse potential and psychotomimetic/dissociative effects. The molecular and neuronal mechanisms underlying the antidepressant actions of ketamine have been intensively studied to pave the way for the development of novel, rapid and more efficacious antidepressants with fewer side effects than ketamine. Preclinical studies demonstrate that ketamine produces antidepressant effects through rapid release and/or expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF), and stimulation of mechanistic target of rapamycin complex 1 (mTORC1) signaling in the medial prefrontal cortex and hippocampus. We have recently found that resolvins (RvD1, RvD2, RvE1, RvE2 and RvE3), bioactive metabolites derived from docosahexaenoic acid and eicosapentaenoic acid, produce antidepressant effects, and that the antidepressant effects of RvD1, RvD2 and RvE1 require mTORC1 activation. These findings suggest that resolvins could be promising targets for the development of novel rapid antidepressants with fewer side effects than ketamine because they are endogenous lipid mediators that play an important role in homeostasis.
Collapse
|
25
|
Kaneda K, Deyama S, Li X, Zhang T, Sasase H. [Neural mechanisms underlying stress-induced enhancement of cocaine craving behaviors]. Nihon Yakurigaku Zasshi 2020; 155:135-139. [PMID: 32378629 DOI: 10.1254/fpj.19147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Stress potentiates craving for addictive drugs including cocaine. To elucidate neural mechanisms underlying this effect of stress, we developed an experimental paradigm combining cocaine-induced conditioned place preference (CPP) with a restraint stress. Acute restraint stress exposure immediately before posttest significantly increased cocaine CPP scores. It has been suggested that the extracellular noradrenaline (NA) level is increased by stress in the laterodorsal tegmental nucleus (LDT), which sends cholinergic projections to dopamine (DA) neurons in the ventral tegmental area (VTA), and medial prefrontal cortex (mPFC), which receives DA input from the VTA. Thus, we investigated the roles of NA in these brain regions. Intra-LDT injection of an α2 or a β adrenoceptor antagonist attenuated the stress-induced enhancement of cocaine CPP. In vitro whole-cell recordings revealed that α2 adrenoceptor stimulation reduced GABAergic inputs to LDT cholinergic neurons that were obtained from cocaine-, but not saline-, treated rats. On the other hand, α1, but not α2 or β, adrenoceptor stimulation excited mPFC pyramidal neurons. Intra-mPFC injection of an α1 adrenoceptor antagonist attenuated the stress-induced enhancement of cocaine CPP. Additionally, chemogenetic silencing of mPFC excitatory neurons also reduced the stress-induced enhancement of cocaine CPP. These findings suggest that stress-induced increases in neuronal activity of the LDT and mPFC may contribute to the enhancement of cocaine craving.
Collapse
|